Electromagnet.



B. G. DUN HAM. ELEOTROMAGNBT. APPLICATION FILED JUNE 4, 1906.

Patented Dec. 20,1910.

UNITED STATES PATENT OFFICE BERT G. DUNHAM, OF ROCHESTER, NEW YORK, ASSIGNOR TO AMERICAN AUTOMATIC TELEPHONE COMPANY, OF ROCHESTER. NEW YORK. A CORPORATION OF NEW YORK.

ELECTROMAGNET.

To (LU whom "it may concern:

Be it known that I, BERT G. DUXHAM, a citizen of the United States, residing at tochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Electromagnets, of which the following is a. specitication, reference being had therein to the ac on'ipanying drawing.

This invention relates to electromagnets and particularly to the type which is used with an electric relay in a telephone exchange system, and it has for an object the prm'ision of a magnet which has quickness and certainty in action, is inexpensive to manufacture and is durable in use.

To this and other ends the invention consists in certain improvements and combinatious of parts all as will be hereinafter more fully described, the novel features being pointed out in. the claims at the end of the Specification.

In the drawings: Figure l is a side view of a magnet constructed in accordance with my invention. Fig. 2 is a. rear end view. Fig. 3 a front end view. Fig. t is a top view, and Fig. 5 is a detail view of the armature.

In the preferred embodiment herein shown a core G is surrounded by the winding which has its terminals to at the front end of the magnet, and to the front and the rear end of the core C are respectively secured, as for instance, by screws to and to pole pieces 0 and c, which extend upwardly and thence toward each other as at c and 0 respectively, over the coil and in the same plane, the extension being as at c depressed or bent at its end toward the winding V to provide a seat for one end of the armature A. The armature A is held on the seat by a plurality of depending spring fingers a having attaching portions 8 secured in a manner to be described and projecting into depressions or seats a. in the upper surface of the armature to permit the armature to complete the magnetic circuit by swinging at its free end which extends beneath the pole piece extension 0 and is provided with an anti-sticking device in the form of a band (a of brass or other nonmagnetic material.

The limit of movement of the armature is controlled by an adjusting device in the form of av screw 6 working through the pole Specification of Letters Patent.

Application filed June 4, 1906.

Patented Dec. 20, 1910. Serial No. 320,151.

piece 0 above the winding and having onehalf of its diameter cut so as to produce a tlat surface which supports the armature and the edges of which when the screw is rotated engage the armature to raise it, a lock nut on the screw acting to hold the latter against movement.

Although the armature may be employed for the control of any suitable device, in the present instance three make and break devices S, S and S are shown as controlled thereby and each comprises three contact springs .9 a and s", secured to the extension 0- with insulating material between them by screws and s which also serves to retain the attaching portion a of the spring 5 before mentioned. These contact springs have terminals 8 and extend parallel to the core 0 to the other pole of the magnet, where the upper and lower ones 8 and 3* are secured to one of the shouldered studs sflwhilethe intermediate one s is apertured so as to move freely about the said stud to permit it to alternately engage springs s and .9 upon the energization and deenergization of the magnet, the intermediate one receiving its motion from the armature A which is connected thereto by one of the studs 8 passing through apertures in extension 0 and in spring 3 The device is preferably supported at its rear end only by a foot 6 bent rearwardly from pole piece 0.

From the foregoing it will be noted that I have provided an electromagnet having positive action, av small time constant and in which the armature while having its ordinary movement in no wise interfered with, is strongly and effectively supported against accidental displacement and at the same time is provided with adjusting means which permits its movement to be varied to agree with an instrument which it is to con trol.

I claim as my invention:

1. In an electromagnet, the comlnnation with a core and a winding therefor, pole pieces secured to the ends of the core, and having ends extending toward each other on one side of the winding and arranged in the same plane, one of saidv pole pieces having its extremity ofi set toward the core and an armature resting in the offset and extending beneath the end of the other pole piece. 2. In an electromagnet, the combination with a core and a winding therefor, of pole pieces secured to the ends of the core and extending toward each other on one side ot' the winding, one of said pole pieces being provided with a depression, and an armature seated in the depression and extending heneath the other pole piece.

:3. In an electroinagnet, a pole piece, an armature resting against and supported on the upper surface of the pole piece, and a spring holding the armature seated therein while permittlng the pivotal movement of the latter.

4-. In an eiectromagnet, a pole piece, an arn'iature resting on the pole piece and provided with a depression, and :1 spring depending into the depression to hold the zil'tlltttlil'e on the pole piece.

In an elcctromagnet the combination with a core, of pole pieces at the ends of the core, one of said pieces extending toward the other at one side of the core and provided with a depressioin an armature resting in the depression, and ii spring secured to the pole piece and having a depending end en gaging and holding the armature in the depression to permit a pivotai movement, of the armature.

(3. In an electroinagnet, the combination with pole pieces, and a pivoted armature, of an adjusting device comprising a screw haw ing a flat surface upon which the armature may lie and the edges of which when the screw is rotated cause the raising of the armature.

T. In an eiectroinagnet, a core, pole pieces at the ends of the core extending toward each ethen an armature pivotaily connected to one pole piece and extending beneath the other, and an adjusting device coi'i'iprising a screw mounted on the last mentioned pole piece and having a fiat surface upon which the armature may he, the edges of which when the screw is rotated causing the raising of the armature.

In testimony whereof I atiix my signature in presence of two witnesses.

BERT G. DURHAM.

\Vitnesses JOSEPH R. IVEnsTER, Gnonen R. Rrxixns. 

